Log Values Research Articles

Numerical estimation of the equivalent hydraulic conductivity for canal concrete lining with cracks

The equivalent saturated hydraulic conductivity of concrete lining (Ksce) is a key parameter to estimate seepage loss, while few studies have quantified the effect of cracks on Ksce, potentially leading to significant errors in canal seepage estimation. A three-dimensional numerical model is employed to simulate seepage loss from canals lined with concrete, and then to obtain the value of Ksce by an equivalent method. A total of 58,400 scenarios are simulated for different concrete lining and crack conditions (e.g., crack length, crack width, crack location, hydraulic conductivity of concrete (Ksc), and underlying soil (Ksoil)), and the corresponding Ksce values are estimated. Results show that the Ksce value determined by the equivalent method is reliable in calculating seepage loss from concrete lined canals. Ksce increases linearly with crack length with a slope Ck, and Ck exhibits a power function relationship with crack width, reaching a maximum value when the crack width surpasses the critical threshold, which ranges from 0.424 to 0.435 mm. When the crack width follows a log-normal distribution, the logarithmic value of Ck increases linearly with the mean value of the logarithmic crack width. The influence of crack location and Ksc on Ksce can be negligible. The maximum increment of Ksce of a crack is proportional to Ksoil. Considering the variation of Ksce with crack parameters and Ksoil, equations to determine the value of Ksce are established by adding the increment of Ksce caused by cracks to Ksc. This study establishes a quantitative relationship between Ksce and crack parameters, thereby enhancing the accuracy of seepage loss calculations in lined canal under different damage status.

QSPR for the prediction of critical micelle concentration of different classes of surfactants using machine learning algorithms

The determination of the critical micelle concentration (CMC) is a crucial factor when evaluating surfactants, making it an essential tool in studying the properties of surfactants in various industrial fields. In this present research, we assembled a comprehensive set of 593 different classes of surfactants including, anionic, cationic, nonionic, zwitterionic, and Gemini surfactants to establish a link between their molecular structure and the negative logarithmic value of critical micelle concentration (pCMC) utilizing quantitative structure-property relationship (QSPR) methodologies. Statistical analysis revealed that a set of 14 significant Mordred descriptors (SlogP, GATS6d, nAcid, GATS8dv, GATS4dv, PEOE_VSA11, GATS8d, ATS0p, GATS1d, MATS5p, GATS3d, NdssC, GATS6dv and EState_VSA4), along with temperature, served as appropriate inputs. Different machine learning methods, such as multiple linear regression (MLR), random forest regression (RFR), artificial neural network (ANN), and support vector regression (SVM), were employed in this study to build QSPR models. According to the statistical coefficients of QSPR models, SVR with Dragonfly hyperparameter optimization (SVR-DA) was the most accurate in predicting pCMC values, achieving (R2 = 0.9740, Q2 = 0.9739, r‾m2 = 0.9627, and Δrm2 = 0.0244) for the entire dataset.

Atomic-scale nucleation pathways of MgAl2O4 particle in molten steel

DFT calculation was used to obtain the structures and thermodynamic properties of (MgAl2O4)n clusters. Atomic-scale nucleation pathway of MgAl2O4 has been discussed by two-step nucleation mechanism. (MgAl2O4)n could formed by five pathways, and the possible pathway from highest to lowest is: the reaction of [Mg], [Al] and [O] > the reaction of [Mg], [O] and (Al2O3)n > the reaction of [Mg] and (Al2O3)n > the reaction of [Mg], [O] and bulk-Al2O3 > the reaction of [Mg] and bulk-Al2O3. (MgAl2O4)n could formed more likely by the reaction of [Mg], [Al] and [O] at the high values of log([%Mg][%Al]2[%O]4), more likely by the reaction of [Mg] and (Al2O3)n at the high values of log([%Mg]3/[%Al]2), more likely by the reaction of [Mg], [O] and (Al2O3)n (or bulk-Al2O3) at the high values of log([%Mg][%O]). Thermodynamic driving force for the formation, aggregation and transformation of (MgAl2O4)n increased with the decreasing of temperature.

Long‐term durability of thermoplastic elastomer containing antiviral additives for mobility applications

AbstractIn the mobility market, there is a demand from customers for antimicrobial protection. As a result, the market has grown considerably to provide antiviral and antimicrobial polymers and coatings. This study examines how the efficacy of a non‐commercial antimicrobial thermoplastic elastomer will change over the life of the application. Using an example application of an electric scooter handlebar grip, durability requirements were identified, and antiviral efficacy (exceeding a log value of 3 or >99.9 microbial growth reduction) was compared before and after testing. A scooter handlebar grip was selected as the ideal example application as it was a high‐touch surface, with several different riders. During the start of this study, scooter companies were encouraging their riders to disinfect scooter handlebars before riding, use hand sanitizer, and wear gloves. If the handlebar grip could be antimicrobial, then they could eliminate these steps and provide a safe ride for the users. In order to simulate long‐term durability, UV exposure, temperature, humidity, artificial sweat, sunscreen, insect repellent, and abrasion tests were performed and evaluated in terms of antiviral activity. Accelerated weathering reduced the virucidal activity of the sample versus unexposed antiviral thermoplastic elastomer (TPE). However, the efficacy increased with contact time from 90% to 96.83% at 30 and 120 min, respectively. Abrasion resistance of antiviral TPE showed a volume loss of 66 mm3 compared to control samples of 83 mm3. The antiviral TPE sample exhibited slightly lower efficacy compared to the control after exposure to the artificial sweat (99.43% vs. 99.95%). Additionally, a skin tolerance test conducted on rabbits showed that antiviral TPE was not an irritant and showed no dermal toxicity. The outcome of this study will lead to the development of long‐term durable antimicrobial material for the transportation industry.Highlights The effectiveness of an antimicrobial material depends on various environmental factors. Accelerated weathering of the antiviral TPE reduced the efficacy. The antiviral TPE was non‐irritating to the skin. Significant research needs to continue in this area to provide safe and robust solutions. This approach to antimicrobial incorporation can now be applied to the transportation industry.

Antimatter Enigma Solved: Astronomical Data Allows Identification of 77 Supermassive Antimatter Black Holes and 23 Antimatter Galaxies.

Initial results from the Alpha-CERN antihydrogen experiment indicate no discernible difference in the gravitational behavior between matter and antimatter, challenging CP violation models. Given that antimatter exhibits the same gravitational behavior as matter, distinguishing between a supermassive black hole (SMBH) composed of matter and an antimatter supermassive black hole (ASMBH) becomes challenging, as their gravitational effects are indistinguishable. This raises the question: Could the SMBH in the Milky Way, and all observed spiral galaxies, potentially be an ASMBH, with its event horizon concealing the equivalent number of antimatter particles, thereby preventing matter-antimatter destruction within a matter galaxy? This article assesses astronomical data comparing the mass of 100 SMBHs with their host galaxies. A theoretical value for the logarithmic mass relationship Log( MStellar /MSMBH ) is presented: 2.963 for ASMBHs situated in matter galaxies, and 2.285 for MSBHs in antimatter galaxies. This relationship, derived from the Ulianov Theory, is based on the premise of matter galaxy formation from protons and electrons expelled by ASMBHs during cosmic inflation. The same theory also posits antimatter galaxy formation from antiprotons and positrons released by matter SMBHs during this period. The database analysis (of 100 galaxies and their respective SMBHs) revealed that 77% of the SMBHs are composed of antimatter, resulting in a logarithmic relationship value of (2.945 ± 0.018) for the Log(MStellar/MASMBH ), while 23% are composed of matter, resulting in a value of (2.267 ± 0.036) for the Log( MAStellar/MSMBH). The congruence between these values and the theoretical prediction is likely not mere coincidence. A thorough examination of the results confirms the model's validity and underscores the precision of astronomers' mass measurements, with only 3 cases showing actual measurement errors beyond the predicted range. This discovery is pivotal, as it suggests the Ulianov Theory's potential to produce novel predictions, such as this model. Originating from a cold and empty universe, this model outlines the galaxy mass formation process, in which ASMBHs harness energy from cosmic inflation, converting it into matter and antimatter particles. This process is termed the "Small Bang" model by the author, reflecting its cold and gradual nature, contrasting the explosive nature of the "Big Bang".

Deep Dive into the factors influencing acoustic velocity in the Dalan-Kangan formations, the central Persian Gulf

The propagation of acoustic waves in rocks is directly influenced by the rocks’ elastic properties. To evaluate petrophysical properties from acoustic data, it is essential to understand the factors that influence the variations in acoustic velocity of sedimentary rocks. Carbonate reservoirs are heterogeneous, and their evaluation is complicated. A closer look at the factors affecting the elastic properties of these rocks is essential because they reveal important information about the reservoir properties and their formation evaluation. Rock physics modeling relies on laboratory-measured acoustic data. This study, however, employs acoustic logs to elucidate the key factors influencing sonic velocity, offering a more comprehensive and field-applicable perspective. Samples were prepared from the Permian–Triassic Upper Dalan and Kangan formations. Porosity, permeability, sedimentary textures, mineralogy, and pore types were investigated. Furthermore, compressional, shear, and Stoneley well-logs data were recorded and converted to acoustic velocity in the sampled interval. Porosity-velocity modeling based on the differential effective medium (DEM) theory was performed for different values of equivalent pore aspect ratio (EPAR). The results show that there is a strong inverse relationship between acoustic velocities and porosity. Acoustic velocities also exhibit an inverse correlation with permeability, but the strength of these relationships is relatively weak. Acoustic velocities are not affected by carbonate textures. A specific texture may exhibit different velocities due to the influence of diagenetic processes. Mineralogy has only a minor influence on acoustic velocities. Dolostones have a slightly higher velocity than limestones, but the difference is insignificant. Stoneley log values are slightly different in limestone and dolostone, because this wave propagates along the mud-borehole interface. The velocities were affected by the variations in pore types within the studied formations. Therefore, in carbonate rocks, porosity, and the pore types play a significant role in controlling acoustic velocities. The value of EPAR = 0.15 can be considered as the boundary between stiff pores (moldic and vuggy) and soft pores (interparticle, intercrystalline, micro-intercrystalline, and microporosity). The lower EPAR value of interparticle pores in limestones compared to dolostones can be attributed to diagenetic processes such as dolomitization and compaction. The findings of this study can help to better understand what factors affect acoustic velocity in carbonate rocks. This study also shows that acoustic logs data can be effectively used in rock physics modeling and pore type identification. By identifying the pore types, it is possible to recognize diagenetic processes and determine the rock types to control the heterogeneity and estimate reservoir quality.

A GIS-based Binary Logistic Regression Model for the Inundation Analysis; A Case Study on Elapatha DS Division, Ratnapura District, Sri Lanka


 
 
 Flood susceptibility analysis (FSA) is a prerequisite for adopting flood mitigation and adaptation techniques. A number of technologies and models have emerged through time, and this study focuses on the Binary Logistic Regression Model (BLRM) to investigate flood vulnerability of Elapatha Divisional secretariat (DS), Ratnapura District, Sri Lanka where has high impact from inundation. Rainfall, land use and land cover (LULC), elevation, slope, slope aspect, distance to the river, topographic wetness index (TWI), and stream power index (SPI) were the factors used in the model construction. These components were investigated in terms of their contribution to flood susceptibility using all location data and field plotting of responsible parameters in the study area using Geographic Information System (GIS) software, and all extracted data points were 96489, of which 50% were used for BLRM development using SPSS statistical software and remaining 50% for model validation. The coefficient of rainfall parameters, log value of elevation in meters, the tan value of slope in degrees, radiant value of aspect in degrees, (distance from the river)0.1, the ratio between SPI and TWI (SPI/TWI) and LULC band values of built-up area, water bodies and vegetations were 0.023, -2.254, -1.018, -0.005, -0.164, -0.003, 2.707, -.067 and -0.004 respectively. The accuracy was validated using Mean standard error (MSE) and area under curve (AUC) analysis, with values of 0.031 and 0.724 respectively. The Built-up area, elevation, and slope had the most impact on the inundation Elapatha DS division, and model performance represents 72.4% accuracy. Therefore, mitigation of inundation problems can be achieved through proper landscaping in the area.
 Keywords: Binary logistic Regression, Flood susceptibility Analysis, GIS software, Spatial analysis
 
 

Nanocrystals Incorporated with Mordenite Zeolite Composites with Enhanced Upconversion Emission for Cu2+ Detection.

In this research, upconversion nanocrystals incorporated with MOR zeolite composites were synthesized using the desilicated MOR zeolite as a host for the in situ growth of NaREF4 (RE = Y, Gd) Yb/Er nanocrystals. The structure and morphology of the composites were studied with XRD, XPS, and TEM measurements, and the spectral studies indicated that the subsequent thermal treatment can effectively improve the upconversion emission intensity of Er3+. By using the NaYF4:Yb/Er@DSi1.0MOR-HT composite that holds the strongest upconversion emission, a probe of UCNC@DSiMOR/BPEI was constructed with the modification of branched poly ethylenimine for the detection of Cu2+. It was indicated that the integrated emission intensity of Er3+ shows a linear dependence with the logarithm value of the Cu2+ concentration ranging from 0.1 to 10 μM. This study offered a feasible method for the construction of UCNC@zeolite composites with enhanced upconversion emission, which may have a potential application as fluorescent probes for the detection of various metal ions by adjusting the doping luminescent center.

Early onset diagnosis in Alzheimer’s disease patients via amyloid-β oligomers-sensing probe in cerebrospinal fluid

Amyloid-β (Aβ) oligomers are implicated in the onset of Alzheimer’s disease (AD). Herein, quinoline-derived half-curcumin-dioxaborine (Q-OB) fluorescent probe was designed for detecting Aβ oligomers by finely tailoring the hydrophobicity of the biannulate donor motifs in donor-π-acceptor structure. Q-OB shows a great sensing potency in dynamically monitoring oligomerization of Aβ during amyloid fibrillogenesis in vitro. In addition, we applied this strategy to fluorometrically analyze Aβ self-assembly kinetics in the cerebrospinal fluids (CSF) of AD patients. The fluorescence intensity of Q-OB in AD patients’ CSF revealed a marked change of log (I/I0) value of 0.34 ± 0.13 (cognitive normal), 0.15 ± 0.12 (mild cognitive impairment), and 0.14 ± 0.10 (AD dementia), guiding to distinguish a state of AD continuum for early diagnosis of AD. These studies demonstrate the potential of our approach can expand the currently available preclinical diagnostic platform for the early stages of AD, aiding in the disruption of pathological progression and the development of appropriate treatment strategies.

Accurate and experimentally validated transition data for Si I and Si II

Aims. The aim of this study is to provide radiative data for neutral and singly ionised silicon, in particular for the first experimental oscillator strengths for near-infrared Si I lines. In addition, we aim to perform atomic structure calculations both for neutral and singly ionised silicon while including lines from highly excited levels. Methods. We performed large-scale atomic structure calculations with the relativistic multiconfiguration Dirac-Hartree-Fock method using the GRASP2K package to determine log(𝑔ƒ) values of Si I and Si II lines, taking into account valence-valence and core-valence electron correlation. In addition, we derived oscillator strengths of near-infrared Si I lines by combining the experimental branching fractions with radiative lifetimes from our calculations. The silicon plasma was obtained from a hollow cathode discharge lamp, and the intensity-calibrated high-resolution spectra between 1037 and 2655 nm were recorded by a Fourier transform spectrometer. Results. We provide an extensive set of accurate experimental and theoretical log(𝑔ƒ) values. For the first time, we derived 17 log(𝑔ƒ) values of Si I lines in the infrared from experimental measurements. We report data for 1500 Si I lines and 500 Si II lines. The experimental uncertainties of our ƒ-values vary between 5% for the strong lines and 25% for the weak lines. The theoretical log(𝑔ƒ) values for Si I lines in the range 161 nm to 6340 nm agree very well with the experimental values of this study and complete the missing transitions involving levels up to 3s23p7s (61 970 cm−1). In addition, we provide accurate calculated log(𝑔ƒ) values of Si II lines from the levels up to 3s27f (122 483 cm−1) in the range 81 nm to 7324 nm.

Abstract WP118: Ischemic Core Volumes and Collateral Status Have Diurnal Fluctuations - A Retrospective Cohort Study of 18137 Patients Using Automated Perfusion Imaging

Introduction: Circadian rhythms have recently been shown to influence stroke incidence and progression of infarct. We aimed to describe the diurnal variations in the incidence and perfusion profiles of patients with ischemic stroke using a large, multi-center, automated imaging database. Methods: The RAPID Insights database was queried from 02/01/2016 to 01/31/2022 for patients with perfusion imaging and automated detection of an ischemic stroke due to a presumed large vessel occlusion. Exclusion criteria included: patient age ≤25, mismatch volume of <0 cc, and failure to register a positive value on either cerebral blood flow (CBF) reduction of 38% less than normal or total mismatch volume. Imaging time was subdivided into three epochs: Night: 23:00h-06:59h and Day: 07:00h-14:59h, and Evening: 15:00h-22:59h. Perfusion parameters were defined as the following: core volume was defined as CBF of <30% of normal, penumbra was defined as a Tmax delay of >6 seconds minus core volume, and collateral circulation was estimated with the Hypoperfusion Intensity Ratio (HIR = [Tmax>10s]/[Tmax>6s]), where a higher HIR suggests poorer collateral status. All perfusion parameters were analyzed on a 24-hour continuous cycle. Statistical significance was tested using a sinusoidal regression analysis. Results: A total of 18,137 cases were analyzed. The peak incidence of ischemic stroke occurred around noon. A sinusoidal pattern was present, with larger ischemic core volumes and higher HIR during the night compared to the day: peak ischemic core volume of 23.40 cc occurred with imaging performed at 3:56 AM (p<0.001) and peak HIR of 0.35 at 3:40 AM (p<0.001). Conclusion: We found that ischemic core volumes were larger and collateral status worse at nighttime compared to daytime in this large national database. These findings support the notion that poor collateral recruitment with subsequent larger ischemic stroke volumes may occur at night. Fig 1. Logarithmic values of ischemic core volumes and hypoperfusion intensity ratios (HIR) are plotted against a 24-hour cycle, demonstrating a sinusoidal pattern for both.

Influence of organic fertilization on growth and yield of strawberry (Fragaria × ananassa) in Kabete and Mbooni areas, Kenya

Strawberries are a valuable crop in Kenya with the potential for significant economic contributions. However, strawberry production in the country has been facing considerable challenges, impacting its economic potential. This study examined the influence of organic manure on strawberry growth and characteristics in Kabete and Mbooni areas in Kenya. The study used a randomized complete block design (RCBD) with three replications. Treatments included livestock manure (well composted mixture of chicken, goat, and cow manure), bokashi manure, and a control, coded as LivManure, BokManure and Control, respectively. Growth parameters including leaf area, number of white flowers and number of runners, as well as yield parameters such as the number and weight of strawberries were assessed from the 3rd to 10th week after transplanting, during the short rain season of 2021. Using R statistical software, linear models were fitted to datasets from both study sites and analyzed using one-way ANOVA, followed by post-hoc tests for multiple comparisons. The rigorous analysis of the Kabete and Mbooni datasets provided insightful revelations about the influence of different treatments on strawberry characteristics, and geographical disparities between the two regions. The analysis of variance (ANOVA) outcomes unveiled significant treatment effects in both sites, with F(2,69) = 62.57, p < 0.001 for Kabete and F(2,69) = 49.02, p < 0.001 for Mbooni, highlighting distinct influences of treatments on log values within each group. Post hoc analyses, including Tukey tests and bootstrap comparisons robustly validated the significant differences among the three treatments in each site, supported by p-values <0.001. Effect sizes were also employed to reinforce the findings, and planned contrasts were set to gain more power in the analysis of variance. Comparison between Kabete and Mbooni indicated a significant difference of 9.78 units, with Mbooni area exhibiting significantly higher strawberry characteristics compared to Kabete. The results showed that LivManure treatment had the highest mean in both sites, followed by BokManure and Control treatments, respectively. These findings have important implications for agriculture, and highlight the potential benefits of using LivManure treatment to improve strawberry characteristics in similar agroclimatic settings. These observations can be attributed to the beneficial effects of livestock manure on soil health, which include buffering of the soil reaction, provision of essential plant nutrients and enhancement of soil faunal activities. Balanced use of livestock manure is recommended to enhance soil macro and micronutrients, and soil reaction for improved growth and yield of strawberry.

Improving Cointegration-Based Pairs Trading Strategy with Asymptotic Analyses and Convergence Rate Filters

AbstractA pairs trading strategy (PTS) constructs a mean-reverting portfolio whose logarithmic value moves back and forth around a mean price level. It makes profits by longing (or shorting) the portfolio when it is underpriced (overpriced) and closing the portfolio when its value converges to the mean price level. The cointegration-based PTS literature uses the historical sample mean and variance to establish their open/close thresholds, which results in bias thresholds and less converged trades. We derive the asymptotic mean around which the portfolio value oscillates. Revised open/close thresholds determined by our asymptotic mean and standard derivations significantly improve PTS performance. The derivations of asymptotic means can be extended to construct a convergence rate filter mechanism to remove stock pairs that are unlikely to be profitable from trading to further reduce trading risks. Moreover, the PTS literature oversimplifies the joint problem of examining a stock pair’s cointegration property and selecting the fittest vector error correction model (VECM). We propose a two-step model selection procedure to determine the cointegration rank and the fittest VECM via the trace and likelihood ratio tests. We also derive an approximate simple integral trading volume ratio to meet no-odd-lot trading constraints. Experiments from Yuanta/P-shares Taiwan Top 50 Exchange Traded Fund and Yuanta/P-shares Taiwan Mid-Cap 100 Exchange Traded Fund constituent stock tick-by-tick backtesting during 2015–2018 show remarkable improvements by adopting our approaches.

Optimization of cold plasma processing conditions for fresh-cut kiwifruit slices by using response surface methodology.

The work aims to optimize the process of cold plasma for fresh-cut kiwifruit. The effects of discharge times, treatment voltages, and slice thickness as well as the interaction between them were investigated. Factor analysis was used to screen out the characteristic indices of fresh-cut kiwifruit. Design-Expert software was used to design three-factor response surface tests and find the optimal parameters. The results revealed that the quality indices of fresh-cut kiwifruit were the color difference, brittleness, and solid-acid ratio, the established binomial regression equations were significant (P < 0.05). At the optimal level: 26 kV treatment voltage, 120 s discharge times, and 10 mm slice thickness, the optimized test values for the color difference, brittleness, solid-acid ratio and decreased logarithm value of total plate count were 2.25, 128.96 g·s, 18.03 and 2.30 lg(CFU·g-1), respectively. Cold plasma could significantly improve the inactivation of bacteria in fresh-cut kiwifruit.

Air-Stable Coordinatively Unsaturated Ruthenium(II) Complex for Ligand Binding and Catalytic Transfer Hydrogenation of Ketones from Ethanol.

Coordinatively unsaturated complexes are interesting from a fundamental level for their formally empty coordination site and, in particular, from a catalytic perspective as they provide opportunities for substrate binding and transformation. Here, we describe the synthesis of a novel underligated ruthenium complex [Ru(cym)(N,N')]+, 3, featuring an amide-functionalized pyridylidene amide (PYA) as the N,N'-bidentate coordinating ligand. In contrast to previously investigated underligated complexes, complex 3 offers potential for dynamic modifications, thanks to the flexible donor properties of the PYA ligand. Specifically, they allow both for stabilizing the formally underligated metal center in complex 3 through nitrogen π-donation and for facilitating through π-acidic bonding properties the coordination of a further ligand L to the ruthenium center to yield the formal 18 e- complexes [Ru(cym)(N,N')(L)]+ (4: L = P(OMe)3; 5: L = PPh3; 6: L = N-methylimidazole; 7: L = pyridine) and neutral complex [RuCl(cym)(N,N')] 8. Analysis by 1H NMR and UV-vis spectroscopies reveals an increasing Ru-L bond strength along the sequence pyridine <1-methylimidazole < PPh3 < P(OMe)3 with binding constants varying over 3 orders of magnitude with log(Keq) values between 2.8 and 5.7. The flexibility of the Ru(PYA) unit and the ensuing accessibility of saturated and unsaturated species with one and the same ligand are attractive from a fundamental point of view and also for catalytic applications, as catalytic transformations rely on the availability of transiently vacant coordination sites. Thus, while complex 3 does not form stable adducts with O-donors such as ketones or alcohols, it transiently binds these species, as evidenced by the considerable catalytic activity in the transfer hydrogenation of ketones. Notably, and as one of only a few catalysts, complex 3 is compatible with EtOH as a hydrogen source. Complex 3 shows excellent performance in the transfer hydrogenation of pyridyl-containing substrates, in agreement with the poor coordination strength of this functional group to the ruthenium center in 3.

Explosion incidents associated with comprehensive studies on methyl ethyl ketone peroxide under thermal decomposition: A review

AbstractThis review gathered and discussed the available results on the thermal hazards, thermal kinetics, decomposition mechanism, autocatalytic behavior, thermal explosion, deflagration ability, and incompatibility hazards associated with the thermal decomposition of methyl ethyl ketone peroxide (MEKPO). The present review constructed a diagram showing all activation energy Ea and log A values for the thermal decomposition of MEKPO. Some disagreement exists in the values of Ea and log A (unit: s−1 M1−n) derived from differential scanning calorimetry; thus, more extensive studies must be conducted to resolve disputes. Nearly no literature exists on the thermal explosion and deflagration ability of MEKPO, and the reactions of MEKPO with incompatible contaminants remain unclear. Concerning the complex decomposition mechanism of MEKPO, experimental determination and identifications of intermediates have not been obtained. Available technology must be improved to enable the collection of accurate data on thermal hazards, thermal kinetics, decomposition mechanisms, explosion and deflagration phenomena, autocatalytic behavior, and incompatibility. This review has integrated an up‐to‐date summary of the most recent approaches and offers perspectives regarding future research. These current findings can serve as a reference for completing subsequent experimental investigations, theoretical studies, and designs of inherently safer measures for producing or handling MEKPO.

A SERS aptasensor based on HCR mediated signal conversion strategy for the rapid and reliable determination of Escherichia coli O157:H7

Rapid and reliable determination of pathogenic bacteria is crucial for food safety and public health. Surface-enhanced Raman spectroscopy (SERS) based aptasensors have attracted increasing attention in the determination of pathogenic bacteria due to their high specificity and sensitivity. However, the sensitivity and reliability of the SERS aptasensors for the determination of pathogens were hindered by the uneven distribution of SERS tags. To tackle this limitation, a SERS aptasensor based on a hybridization chain reaction (HCR) mediated signal conversion strategy was fabricated for the determination of E. coli O157:H7. In the presence of E. coli O157:H7, the blocked aptamer specifically binds with it and releases the blocker DNA. Then the blocker DNA hybridizes with the capture DNA on the SERS probe and initiates the HCR reaction, which further leads to the formation of double stranded DNA and the reduction of the SERS signal intensity of 4-mercaptobenzonitrile (4-MBN). Under the optimal conditions, the SERS signal intensity at 1073.9 cm−1 and the logarithmic value of the concentration of E. coli O157:H7 in the range of 8 × 102–8 × 107 CFU·mL−1 exhibited a good linear relationship, with a coefficient of determination of 0.92. The limit of detection for E. coli O157:H7 was 409 CFU·mL−1. Besides, this aptasensor exhibited satisfactory specificity for E. coli O157:H7. In addition, it showed excellent stability in real sample analysis with relative standard deviations (RSDs) below 3.76 % (n = 3). The established SERS aptasensor employed a HCR mediated signal conversion strategy and overcame the drawback of unevenly distribution of SERS tags in classical SERS aptasensors for the determination of pathogenic bacteria. This study offered a new reference for the rapid and reliable detection of pathogens with a portable Raman spectrometer.

Effect of a novel pH-responsive tertiary amine monomer dodecylmethylaminoethyl methacrylate modified resin adhesive on biofilm formation of Streptococcus mutans and Lactobacillus casei in vitro

Objective: To explore the application prospect of a new pH-responsive tertiary amine monomer dodecylmethylaminoethyl methacrylate (DMAEM) modified resin adhesive (DMAEM@RA) in the prevention and treatment of secondary caries. Methods: Five percents DMAEM was added to the resin adhesive to synthesize DMAEM@RA for modifying. Streptococcus mutans (Sm) and Lactobacillus casei (Lc) biofilms were cultured on resin adhesive and DMAEM@RA, respectively. The culture systems were set up at pH=7.4, 6.0, 5.5, and 5.0. The antimicrobial activity of DMAEM@RA was evaluated by quantitative PCR. The effects of DMAEM@RA on biofilm thickness, bacterial amount, and extracellular polysaccharides were studied by scanning electron microscope (SEM) and extracellular polysaccharide staining. Real-time fluorescence quantitative PCR was used to study the effect of DMAEM@RA on the expression levels of cariogenic genes in Sm. Results: DMAEM@RA could significantly reduce the amount of Sm and Lc under acidic conditions, especially Lc. At pH=5.0, the logarithm value of co-cultured Sm bacteria [lg (CFU/ml)] in DMAEM@RA group (7.58±0.01) was significantly lower than that in control group (7.87±0.03) (t=14.32, P<0.001), and the logarithm value of Lc bacteria [lg (CFU/ml)] (7.29±0.04) was also significantly lower than that in control group (7.93±0.15) (t=6.93, P=0.002). SEM observed that the bacteria decreased and the cell fragments appeared in DMAEM@RA group. In addition, DMAEM@RA significantly reduced the biomass of extracellular polysaccharides in the dual-species biofilm under acidic conditions. At pH=5.0, the biomass of extracellular polysaccharides in DMAEM@RA group [(25.13±3.14) mm3/mm2] was significantly lower than that in the control group [(42.66±7.46) mm3/mm2] (t=3.75, P=0.020). DMAEM@RA could significantly up-regulate the expressions of gtfB and gtfC genes in Sm under acidic conditions. At pH=5.0, gtfB and gtfC genes were significantly up-regulated by (14.64± 0.44) times and (2.99±0.20) times, respectively (t=-42.74, P<0.001; t=-13.55, P<0.001). Conclusions: The DMAEM@RA has a good antibacterial effect under acidic conditions, demonstrating that it has a good potential to prevent the occurrence and development of secondary caries.

Retention of Virus Versus Surrogate, by Ultrafiltration in Seawater: Case Study of Norovirus Versus Tulane.

In the field of chemical engineering and water treatment, the study of viruses, included surrogates, is well documented. Often, surrogates are used to study viruses and their behavior because they can be produced in larger quantities in safer conditions and are easier to handle. In fact, surrogates allow studying microorganisms which are non-infectious to humans but share some properties similar to pathogenic viruses: structure, composition, morphology, and size. Human noroviruses, recognized as the leading cause of epidemics and sporadic cases of gastroenteritis across all age groups, may be mimicked by the Tulane virus. The objectives of this work were to study (i)the ultrafiltration of Tulane virus and norovirus to validate that Tulane virus can be used as a surrogate for norovirus in water treatment process and (ii) the retention of norovirus and the surrogate as a function of water quality to better understand the use of the latter pathogenic viruses. Ultrafiltration tests showed significant logarithmic reduction values(LRV) in viral RNA: around 2.5 for global LRV (i.e., based on the initial and permeate average concentrations) and between 2 and 6 for average LRV(i.e., retention rate considering the increase of viral concentration in the retentate), bothfor norovirus and the surrogate Tulane virus. Higher reduction rates (from 2 to 6 log genome copies) are obtained for higher initial concentrations (from 101 to 107 genome copies per mL) due to virus aggregation in membrane lumen. Tulane virus appears to be a good surrogate for norovirus retention by membrane processes.

Modelling the evolution of water retention hysteresis loops during soil deformation based on the ink‐bottle effect

AbstractThe ink‐bottle effect, resulting from the heterogeneous pore structure, plays a significant role in the hydraulic hysteresis of water retention behavior. Experimental evidence indicates that volumetric deformation extensively influences the hysteresis characteristics of the soil‐water retention curve (SWRC). This paper presents a physical–based model that aims to simulate the contraction of the hysteresis loop in the SWRC during soil compression by considering the evolution of the ink‐bottle effect. Within the proposed model, it is assumed that the suction increment is consumed in two distinct manners: to overcome the ink‐bottle effect and to alter soil saturation. As soil undergoes compression, the ink‐bottle effect weakens, resulting in a reduced proportion of suction consumed in counteracting this effect. To quantitatively describe the impact of ink‐bottle effect evolution on SWRC hysteresis, a novel concept known as hysteresis potential is introduced, which is defined as the difference in natural logarithmic values of suction between the drying and wetting curves at a given saturation. Finally, the proposed model was validated using five sets of experimental data, affirming its capability to capture the hysteresis loop evolution in SWRC attributed to the weakening of the ink‐bottle effect during soil compression.